RFR: 8349088: De-virtualize Codeblob and nmethod

[Vladimir Kozlov]

On Sun, 9 Feb 2025 17:45:30 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

> Remove virtual methods from CodeBlob and nmethod to simplify saving/restoring in Leyden AOT cache. It avoids the need to patch hidden VPTR pointer to class's virtual table.
> 
> Added C++ static asserts to make sure no virtual methods are added in a future.
> 
> Fixed/cleaned SA code which process CodeBlob and its subclasses. Use `CodeBlob::_kind` field value to determine the type of blob.
> 
> Tested tier1-5, hs-tier6-rt (for JFR testing), stress, xcomp

@dougxc and @tkrodriguez,  please look if it affects Graal.

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PR Comment: https://git.openjdk.org/jdk/pull/23533#issuecomment-2646553512